He received his military training at Royal Military Academy Sandhurst, England. In the 1930's and early 1940's, Mirza occupied important posts in the colonial administration of Orissa and the North West Frontier Province in British India. From 1948 to 1952 he served as Secretary to the Government. In 1954, he was appointed Governor of East Pakistan and from 1954 to 1955 he was Minister for Interior. He was the last Governor-General from September 1955 to March 1956 before Pakistan established its first constitution, replacing the Governor-General with the President, making him the first President of Pakistan, from March 1956 to 24 October 1958.